524 E. HUNTIXGTON SOLAR HYPOTHESIS OF CLIMATIC CHANGES 



much more than the cold air, and hence the total result must probably 

 be to lower the temperature. 



In polar regions the effect would be different. Eecent explorations 

 have established the fact that Antarctica and the great ice-cap of Green- 

 land are regions of high pressure, and hence of descending air. The 

 temperature of this air depends on the degree to which the air which has 

 ascended in other places has had time to give off its heat before it begins 

 to descend. It seems probable that when a given body of warm air rises 

 in equatorial or temperate regions it stays aloft so long that when a por- 

 tion of it finally descends in the midst of a polar area of high pressure 

 it has lost as much heat as it can by radiation — ^that is, its temperature 

 will be almost the same, no matter how warm it may have been when it 

 rose. In that case the temperature of polar regions will suffer little 

 change except in so far as there is a variation in the amount of heat 

 received from the sun. 



In view of the conditions here described, it appears as if changes in 

 the storminess of the earth must cause changes in the mean temperature 

 of the atmosphere at low levels, even without any change in the amount of 

 heat received from the sun. The variations would take place in accord- 

 ance with the phenomena which we actually observe and which have been 

 tabulated by Koppen and others. 



A possible magnetic or electric cause of cyclonic storms. — The verity 

 of the conclusion just reached depends in part on the cause which future 

 investigation may assign to cyclonic storms. We have seen that such 

 storms seem to be directly connected with changes in the sun. We have 

 also seen that certain phenomena, such as the apparent absence of any 

 effect of volcanic eruptions on storminess, seem to imply that the loca- 

 tion and intensity of storms is not due primarily to temperature alone. 

 Kullmer has advanced some interesting reasons for suspecting some con- 

 nection between storms and terrestrial magnetism. He points out that 

 there are three centers of storminess, corresponding to the three magnetic 

 poles. In the southern hemisphere there is only one magnetic pole. The 

 cyclonic storms of that region circle around it in about latitude 60° 

 south. ^^ Their average path is not concentric with the pole of rotation, 

 but with the magnetic pole. In the northern hemisphere the main mag- 

 netic pole lies in the northeastern part of jSTorth America, approximately 

 in latitude 70° north and longitude 97° west. Corresponding to this we 

 have the main stormv area of the world. It extends from the western 



^ See W. J. S. Lockyer : Southern Hemisphere. Surface air circulation. London, 1910. 

 Also National Antarctic Expedition, 1901-1904 : Meteorology, Part II, comprising daily 

 synchronous charts, 1st October, 1901, to 31st March. 1904. London, Royal Society. 

 1913. 



